The invention relates to contactless rotary joints specifically for transfer of high levels of electrical power, also called rotating power transformers. Such contact-less rotary joints may be used in CT scanners.
A contactless rotary joint comprising an inductive power coupler is disclosed in U.S. Pat. No. 7,197,113 B1. Such a rotary joint is able to transfer power of more than hundred kilowatts from a stationary part to a rotating part. Rotary joints enabled to transfer such high levels of power have heavy iron- or ferrite-based cores for guiding the magnetic fields. For example, in a typical CT scanner, a free bore diameter of more than one meter is required. Accordingly, the inner diameter of a rotary joint configured for use with the CT scanner may be more than 1 meter, and the rotary joint would require large and massive mechanical support structures.
The European patent publication EP 1 481 407 B1 discloses a rotating transformer with a winding form made of a plurality of shaped parts held within a U-shaped ring.